Chemical structures and immunolocalization of glycosphingolipids isolated from Diphyllobothrium hottai adult worms and plerocercoids

Glycosphingolipids (GSLs) were purified from adults and plerocercoids of the tapeworm Diphyllobothrium hottai , and their chemical structures were determined. Total lipid fractions prepared from chloroform/methanol extracts of whole tissues were fractionated successively on ion‐exchange chromatography, silicic acid column chromatography, and preparative TLC. The purified GSLs were characterized by methylation analysis, TLC‐immunostaining, liquid secondary ion MS, MALDI‐TOF MS, and 1 H‐NMR. Ten GSLs were isolated from adult worms and four from plerocercoids, comprising mono‐, di‐, tri‐, tetra‐, and pentasaccharides. The GSL Galβ1–4(Fucα1–3)Glcβ1–3Galβ1‐Cer was found in adult worms but not in plerocercoids, whereas Galβ1–4 (Fucα1–3)Glcβ1–3(Galβ1–6)Galβ1‐Cer was found in both adult worms and plerocercoids. We previously found a similar series of GSLs in plerocercoids of the cestode Spirometra erinaceieuropaei , and termed them ‘spirometosides’[Kawakami, Y. et al . (1996) Eur J. Biochem . 239 , 905–911]. The core structure of spirometosides, Galβ1–4Glcβ1–3 Galβ1‐Cer, may have taxonomic significance, being characteristic of pseudophyllidean tapeworms. In the present study, GSL compositions were significantly different between adults and plerocercoids, and growth‐dependent changes in composition were documented. We found a novel dihexosylceramide, Glcβ1–3Galβ1‐Cer, which is a possible precursor for spirometosides. Immunohistochemical examination showed that spirometoside GSLs are highly enriched in the inner surface of bothria, the major point of contact between the adult worm and the host's intestine. Our findings indicate that spirometosides are involved in host–parasite interaction.